I went to the kernel page that David McKenna suggested where I found two choices.
The first did not mention a version number, but it turned out to be 14.85_w4. Same svxcore.dll problem as before.
Then I tried 104a_uni, eschewing the _smp per Dave Yeo's post. This is (for now) without dllbase. First attempt, the splash screen showed up and the frame of the new user window appeared, but then it locked up. Inserting a CTRL-ALT-DEL did nothing so I had to reset the guest. I gave it another try once back at the desktop. And this time it worked
And this was with guest RAM set back to 128MB.
Once OS/2 has been in use for a while I will try to launch it again to get an idea of whether dllbase is still needed.
Since this may be the last kernel I can use, is it considered a fairly stable one?